2 22" bass drums. One in a playable condition, played every now and then.
A 16" bass drum - played occasionally.
A 20" bass drum. This is my 'main' drum.

What kind of music I play? Ostensibly 'Rock' but I dabble in other styles and am irritatingly fickle.

So 50% of my bass drums are 22". Of the 'playable' drums, I'm down to 33%. If we take that 33% rather than the 50% then my average size is 19.3 (recurring) inches. In terms of playing time over the last 12 months then it's more like 18.8 - the 22" hasn't been played much since January and I've been playing the 20" since May.